• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1214-1219
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• 2002

Railway signalling system always is required high safety and reliability. The failure of the train control system can provoke a serious accident. In this paper, we show how to achieve the safety and reliability by dividing signalling system into vital and non functions, studying operational environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.10
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• pp.895-903
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• 2016

Spaceborne imaging sensors require periodic calibrations using an on-board calibration device for an image quality of observation satellites. The on-board calibration device consists of a blackbody to provide uniform radiance temperatures and calibration mechanism with a function of stow and deploy to target the blackbody during the calibration. Among these devices, the calibration mechanism is required to implement a fail-safe function to prevent blocking of the main optical path when the mechanism stops at a certain position during on-orbit calibration. In addition, structural safety of the mechanical driving part of the mechanism within the launch environment must be guaranteed. In this study, we proposed a deploy/stow-type calibration mechanism that provides launch-lock and fail-safe function. The effectiveness of the functionality of the proposed mechanism was validated through functional test using engineering model.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.91-96
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• 1996

The Dynamic Safety System (DSS) is a compute. based reactor protection system that has fail-safe nature and perform dynamic self-testing. In this paper, the implementation of DSS in PLC is presented for PWR. In order to choose adequate PLC implementation model of DSS, the reliability analysis is performed. The KO-RI unit 2 Nuclear power plant is selected as the reference plant, and the verification is carried out using the KO-RI unit 2 simulator FISA-2.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.299-312
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• 2021

Autonomous vehicles using V2X can drive safely information on areas outside the sensor coverage of autonomous vehicles conventional autonomous vehicles. As V2X technology has emerged as a key component of autonomous vehicles, research on V2X security is actively underway research on risk analysis due to failure of V2X communication is insufficient. In this paper, the service scenario and function of autonomous driving system V2X were derived by presenting the intersection scenario of the autonomous vehicle, the malfunction was defined by analyzing the hazard of V2X. he ISO26262 Part3 process was used to analyze the risk of malfunction of autonomous vehicle V2X. In addition, a fault injection scenario was presented to verify the fail-safe of the simulation-based intersection scenario.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.56-61
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• 2010

Simulator is a development equipment which enables the ECU to operate in normal mode by simulating the interface signal between ECU and mechanical system electrically. Embedded simulator means simulation function is embedded in ECU firmware, hence the electrical signal interface is replaced by the substitution of information at system program level. This paper explains the development of embedded transmission simulator for the verification of TCU firmware function which covers shifting control and on-board diagnosis. The embedded simulation program is executed in TCU processor along with the TCU firmware and it provides TCU firmware with not only the speed information those are appropriate both in driving and shifting conditions, but also the fault detection signals. Experimental results show that the validity of embedded simulator and its usefulness to the TCU firmware development and verification.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.4
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• pp.1-11
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• 2007

This paper verifies the difference of the seismic behavior and seismic damage of the neighboring two reinforced concrete piers damaged by the 1995 Hyogoken Nanbu earthquake. The two piers were almost the same size, carrying slightly different dead load, and were provided with the same reinforcement arrangement except the amount of longitudinal reinforcement at the bottom portion of the piers. The pier with more reinforcement was completely collapsed due to this near field earthquake by shear failure at the longitudinal reinforcement cut-off while the other was only damaged at the bottom by flexure even though the longitudinal reinforcement cut-off was also existed at the mid height of the pier. According to the results of the pseudo dynamic test, the seismic damage was recognized to be greatly dependent on the ground motion characteristics even though the employed ground motions had the same peak acceleration. The severe damage was observed when the test employed the seismic wave that had strong influence to the longer period range compared to the initial natural period of the pier. On the other hand, based on the similar model experiment, the defect of gas-pressure welded splice of longitudinal reinforcement was revealed to save the piers against collapse due to the so-called fail-safe mechanism contrary to the intuitive opinion of some researchers. It was concluded that the primary cause of the collapse of the pier was the extremely strong intensity and peculiar characteristics of the earthquake motion according to both the site-specific and the structure-specific effects.